Heretofore, transversely (side) pumped dye laser oscillators have been designed such that the polarization of the electric vector of the optical pumping radiation was generally orthogonal to the polarization of the electric vector of the optical wave radiation being amplified within the pumped dye laser gain medium. Such a dye laser is disclosed in U.S. Pat. No. 4,016,504 issued Apr. 5, 1977.
It is also known from the prior art in connection with optically pumped dye lasers of the type wherein the Poynting vector of the pumping light beam is approximately colinear with the Poynting vector of the optical wave radiation being amplified (longitudinally pumped) that the polarization of the electric vector of the pumping radiation and of the optical wave radiation being amplified within the dye laser gain medium are preferably parallel, for improved conversion efficiency. Such a dye laser is disclosed in an article appearing in volume 11, No. 1 of Optics Communications dated May 1974, pages 14-17.